Rif.: Code is Crashing with FATAL RUN-TIME ERROR: General Protection Fault

[RobertoBozzolo]

I second Rolf opinion: getting a GPF with an application crash is absolutely in contrast with you being able to complete the offending function!

So please go and clarify your situation 'cause we cannot understand what's happening

[tps1993]

Hi,

Below is the function from where I am getting GPF.

int TX_FUNC RunSeqChangePreTest()
{
    tTestData dataRec;
    tTestError errorRec;
    int testResult;
    int modIdErr,funcPtrErr;
    
    int saveTxState;

    saveTxState = gTxState;
    gTxState=SEQUENCE_RUNNING;
    dataRec.result = PASS;
    dataRec.inBuffer = NULL;
    dataRec.outBuffer = NULL;
    dataRec.hook = NULL;
    errorRec.errorMessage = NULL;
    errorRec.errorFlag = FALSE;
    errorRec.errorLocation = IN_NONE;
 
    if (TX_VerifyPrePostTest (TRUE,TRUE,&modIdErr,&funcPtrErr) != NO_ERROR)
	{
		
        goto Error;
	}
     MessagePopup("Test","Before TxRun PrePostTest");
    testResult = TX_RunPrePostTest(&dataRec, &errorRec, TRUE, TRUE);
	//TX_RunPrePostTest(&dataRec, &errorRec, TRUE, TRUE);
	MessagePopup("Test","After TxRun PrePostTest"); 
#ifdef REPORT_META_PREPOST_OUTBUF
    
    BeginReportString()
	
    WritePrePostOutBuffer(&dataRec, &errorRec, prePostErr);
    if (dataRec.outBuffer != NULL) {
        free(dataRec.outBuffer);
        dataRec.outBuffer = NULL;
    }
    EndReportString();
#endif
 
    if (testResult != NO_ERROR || errorRec.errorFlag)
        goto Error;
    gTxState = saveTxState;
    return TRUE;
Error:

	 Beep();
    MessagePopup (MSG_LOADSEQ_SETUP_ERR, MSG_LOADSEQ_SETUP_ERR_TITLE);
    gTxState = saveTxState;
    return FALSE;
}

 In the above code it is executing till line 

testResult = TX_RunPrePostTest(&dataRec, &errorRec, TRUE, TRUE);

Program is crashing with GPF before MessagePopup function.

TX_RunPrePostTest is function in another file. Please find code below

int TX_FUNC TX_RunPrePostTest (
    tTestData *data,
    tTestError *err,
    int isMetaTest,
    int isPreTest)
{
	
    Boolean result;
    LLNode *theTest;
    int (TX_FUNC *theTestFuncPtr) (char *parameters, tTestData *data, tTestError *err);
    MessagePopup("Test","Entered RunPrePost");
    if (isPreTest) {
        if (isMetaTest)
            theTest = gTXEngine.hMetaPreTest;
        else
            theTest = gTXEngine.hSeqPreTest;
        if (theTest == NULL)
            return NO_ERROR;
        theTestFuncPtr = theTest->hPreTest;
    } else {
        if (isMetaTest)
            theTest = gTXEngine.hMetaPostTest;
        else
            theTest = gTXEngine.hSeqPostTest;
        if (theTest == NULL)
            return NO_ERROR;
        theTestFuncPtr = theTest->hPostTest;
    }

    /**/
    /* If you are going to actually execute, verify the test status.
    /**/
 
    if (theTestFuncPtr == NULL)
        return TX_ReportEngineError(ERR_TEST_NOT_VERIFIED,theTest->funcName,
            theTest->fileName);

    /**/
    /* Execute Pre/Post Test.
    /**/
    data->modPath = TX_GetFileDir(theTest->fileName);
    data->modFile = TX_GetBaseFileName(theTest->fileName);
    if (theTest->parameters != NULL)
    	data->inBuffer = TX_StrDup(theTest->parameters);
    	
    result = (theTestFuncPtr)
    	(theTest->parameters, data, err);
  
    // Good god
        
    //free(data->modPath);
    //free(data->modFile);
	
    if (err->errorFlag) {
        if (isPreTest) {
            if (isMetaTest) {
                err->errorLocation = IN_META_PRETEST;
                return TX_ReportEngineError(ERR_METAPRETEST_RUN_TIME,
                    theTest->funcName,theTest->fileName);
            } else {
                err->errorLocation = IN_SEQ_PRETEST;
                return TX_ReportEngineError(ERR_SEQPRETEST_RUN_TIME,
                    theTest->funcName,theTest->fileName);
            }
        } else {
            if (isMetaTest) {
                err->errorLocation = IN_META_POSTTEST;
                return TX_ReportEngineError(ERR_METAPOSTTEST_RUN_TIME,
                    theTest->funcName,theTest->fileName);
            } else {
                err->errorLocation = IN_SEQ_POSTTEST;
                return TX_ReportEngineError(ERR_SEQPOSTTEST_RUN_TIME,
                    theTest->funcName,theTest->fileName);
            }
        }
    }
	
    if (!result) {
        if (isPreTest) {
            if (isMetaTest) {
                err->errorLocation = IN_META_PRETEST;
                return TX_ReportEngineError(ERR_META_PRETEST_FAIL);
            } else {
                err->errorLocation = IN_SEQ_PRETEST;
                return TX_ReportEngineError(ERR_SEQUENCE_PRETEST_FAIL);
            }
        } else {
            if (isMetaTest) {
                err->errorLocation = IN_META_POSTTEST;
                return TX_ReportEngineError(ERR_META_POSTTEST_FAIL);
                return TX_ReportEngineError(ERR_META_POSTTEST_FAIL);
            } else {
                err->errorLocation = IN_SEQ_POSTTEST;
                return TX_ReportEngineError(ERR_SEQUENCE_POSTTEST_FAIL);
            }
        }
    }

    if (!result) {
		
        err->errorLocation = IN_SEQ_PRETEST;
        return TX_ReportEngineError(ERR_SEQUENCE_PRETEST_FAIL);
    }

	MessagePopup("test","Completed function");
	
    return NO_ERROR;
} /* END TX_RunPrePostTest () */

But I checked this function. It is executing without issue and Displaying the last message popup also.

Please let me know if you need more details

[RobertoBozzolo]

Ok, so the situation is: the called functions terminates succesfully and you getaGPF error after its execution.

Now, we know nothing about the instructions following the call, in particular those for reporting: have you checked them? Can you step into the code and see what happens there?

Finally, the MessagePopup only fires in case of errors in called functions so it's not a good option for debugging. You could ipothetically get the error elsewhere in your code but you have o no infos on this function termination.

[tps1993]

When I try to debug, am getting a linking error as below:

error: Undefined symbol '__UPLibBreakpointWithElabUtf8' referenced in "c:\Program Files (x86)\National Instruments\Shared\CVI\Bin\msvc\visa.lib".

[RobertoBozzolo]

Well, this could help to discriminate what's happening.

In this respect questions are:

1. Are you actually using VISA in you code?

2. Are there some differences between debug and release configurations? Or #ifdefs or #pragmas that exclude/include some code in relase or debug?

[tps1993]

1. I am using Visa in code

2. There is no difference in release and debug configurations

[RobertoBozzolo]

---

@tps1993  ha scritto:

2. There is no difference in release and debug configurations

---

This is hard to believe: an error like that would prevent the project from compiling!

In any case this guide could help you in solving this building error: Undefined Symbol Error When Compiling LabWindows™/CVI™ Project 

[rolfk]

LabWindows/CVI libraries have a special feature called User Protection. That is extra code added to the entry and exit points of all functions to verify the parameters and return values for consistency and report any potential problem using those __UPxxxxxxx functions.

These UP stubs should only be enabled when you build your project for Debug mode. Something seems to be off with your project. Now this is all very old information. I used to write some CVI libraries more than 20 years ago and wanted to add those extra user protection stubs to my own library for the convenience of users of that library. Someone at NI was nice enough to give me an unofficial document about how this works.

I'm not sure LabWindows/CVI still uses that or even supports it. It seems your visa.lib contains references to such functions but CVI seems not to be able to resolve it to any of its internal libraries.

Possible reason:

- CVI did away with UP functionality and your visa.lib is from an older CVI installation

- Your CVI installation is somehow corrupted and it does not use the correct runtime libraries when you try to run in debug mode

- Your project got corrupted and confuses CVI

[tps1993]

Thanks rolfk

Reinstalling CVI fixed the debugging issue,

Please find the debug failure in the snapshot below. As I mentioned earlier GPF is generated from RunSeqChangePreTest Function which is described in the previous comment

[RobertoBozzolo]

I'm almost afraid to ask...

Now that you have fixed the debug issue, can you step into the code and locate the exact function where the error arises? Place a breakpoint on the line that you have highlighted above and press F8 to execute the code instruction by instruction until you locate the exact line inside RunSeqChangePreTest function that fires this GPF